39921971 has 4 divisors (see below), whose sum is σ = 39934944. Its totient is φ = 39909000.

The previous prime is 39921953. The next prime is 39921977. The reversal of 39921971 is 17912993.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-39921971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (39921977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1046 + ... + 8996.

It is an arithmetic number, because the mean of its divisors is an integer number (9983736).

Almost surely, 2^39921971 is an apocalyptic number.

39921971 is a deficient number, since it is larger than the sum of its proper divisors (12973).

39921971 is an equidigital number, since it uses as much as digits as its factorization.

39921971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12972.

The product of its digits is 30618, while the sum is 41.

The square root of 39921971 is about 6318.3835749343. The cubic root of 39921971 is about 341.7726650561.

The spelling of 39921971 in words is "thirty-nine million, nine hundred twenty-one thousand, nine hundred seventy-one".